U.S. Treasury Secretary Timothy Geithner says as China becomes an increasingly important market for U.S. exports, it must do more to lower unfair trade barriers.

In testimony before the Senate Finance Committee Thursday, Geithner noted that U.S. exports to China are growing much more rapidly than exports to other parts of the world.

But, he said certain Chinese economic policies still leave U.S. businesses at a disadvantage in Chinese markets.

Lawmakers have expressed concern that China is undervaluing its currency, making Chinese goods cheaper to export, and that China is not doing enough to stop the pirating of U.S. intellectual property.

Lawmakers criticized Geithner and the administration of President Barack Obama for not doing enough to address these concerns.

Senate Finance Committee Chairman Max Baucus said China's economic policies are a global concern, but that the United States must take the lead in negotiating change.

Geithner's testimony comes more than a month after U.S. and Chinese officials met face-to-face to discuss mutual concerns at the two-day Strategic and Economic Dialogue in Beijing.

Following that meeting, the treasury secretary announced China had taken steps to modify a so-called "indigenous innovation" policy that favors Chinese companies for government contracts. The United States has complained that this policy leaves American businesses at a disadvantage.

Geithner did not secure a public commitment from China to allow the value of its yuan currency to rise compared to the dollar.

U.S. lawmakers plan to introduce legislation this month that aims to punish China for refusing to raise the value of its currency. The bill would raise import duties and tariffs on products from China or any other country with an exchange rate designed to be misaligned with the U.S. dollar.

Chinese President Hu Jintao has said his government will carry out currency reform, but at its own pace.